Fix map equivalence check.

Comments

Fix map equivalence check.
Given a map, its HasNonInstancePrototype bit in bit_field can differ
from the same bit in that map's root map. If that is the case just
return false from the equivalence check. (Currently, we just assert
that bit_field is the same for a map and its root map.)
Bug: chromium:930486
Change-Id: Ic0eb83f80725fb1224e0f97927127e1cb8ad92e6
Reviewed-on: https://chromium-review.googlesource.com/c/1462004
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59508}